Textured/polished respiratory mask seal and mask

ABSTRACT

A seal for a respiratory mask that includes a first end portion adapted to be coupled to a mask shell, a second end portion for sealing engagement with a face of a patient, and a sidewall extending between the first end portion and the second end portion. At least a portion of the second end portion includes a textured area having a predetermined pattern. The area of increased surface roughness provides the patient contacting portion of the seal with a silky feeling to maximize patient comfort and the effectiveness of the seal without impairing the sealing ability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation under 35 U.S.C. §120 of U.S. patentapplication Ser. No. 13/538,071, filed Jun. 29, 2012, which is aContinuation-in-Part under 35 U.S.C. §120 of U.S. patent applicationSer. No. 12/623,460, filed Nov. 23, 2009, now U.S. Pat. No. 8,230,861,which is a Continuation of U.S. patent application Ser. No. 10/778,444,filed Feb. 13, 2004, now U.S. Pat. No. 7,640,933, the contents of eachof which is incorporated herein by reference

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a seal that has a texturedpatient-contacting surface to improve comfort during contact with thepatient's face and a polished surface to maintain aesthetic appeal, andto a respiratory mask using such a seal.

2. Description of the Related Art

A variety of respiratory masks are known that have flexible seals andcover the nose, mouth, or both of a human patient. The seals, which arealso commonly referred to as cushions, are intended to create a sealagainst the patient's face. Because of the sealing effect that iscreated, gases can be provided at a positive pressure within the maskfor delivery to the airway of the patient.

The uses for such masks range from high altitude breathing, i.e.,aviation applications, to mining and fire fighting applications, tovarious medical diagnostic and therapeutic applications. For example,such masks are used in the delivery of continuous positive airwaypressure (CPAP) or variable airway pressure, such as a bi-level pressurethat varies with the patient's respiratory cycle or an auto-titratingpressure that varies with the monitored condition of the patient.Typical pressure support therapies are provided to treat a medicaldisorder, such as sleep apnea syndrome, in particular, obstructive sleepapnea (OSA), or congestive heart failure.

A requisite of such respiratory masks is that they provide an effectiveseal against the patient's face to prevent leakage of the gas beingsupplied, while also providing a comfortable patient/seal interface.This problem is most crucial because such masks are typically worn foran extended period of time. One concern in such a situation is that apatient may avoid wearing an uncomfortable mask, defeating the purposeof the prescribed pressure support therapy.

Examples of conventional respiratory masks used in the medical field forproviding a positive airway pressure to a patient include U.S. Pat. No.5,243,971, which teaches a bubble-type of patient interface in which theseal is attached to a shell and extends from the shell in a concavefashion. Other conventional masks are disclosed, for example, in U.S.Pat. Nos. 5,540,223 and 6,467,483. A still further type of mask isdescribed in U.S. Pat. No. 5,647,357, which uses a gel material as theseal or cushion to maximize patient comfort and sealing properties. U.S.Pat. No. 4,971,051 teaches a mask in which the seal includes multipleflaps, again to optimize patient comfort and the sealing property.

In each of these conventional seals and others, the patient-contactingsurface of the seal or the flap is very smooth, which is also referredto as being highly polished. Polished surfaces can cause skin irritationin some patients. The present inventors opined that such irritation isthe result of an inability of the skin underlying the polished to“breathe”. That is moisture and/or heat may build up under the polishedcushion. Polished surfaces also tend to feel sticky or tacky to thetouch, causing the seal to stick to the patient's skin. This stickinessmay cause the cushion to dislodge from the shell or faceplate to whichthe seal is mounted rather than shift on the patient if a torque orpulling force is applied on the mask

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a sealfor a respiratory mask that overcomes the shortcomings of conventionalpatient interface devices. This object is achieved according to oneembodiment of the present invention by providing a seal for arespiratory mask that includes a first end portion adapted to be coupledto a mask shell, a second end portion for sealing engagement with a faceof a patient, and a sidewall extending between the first end portion andthe second end portion. At least a portion of the second end portionincludes a textured area having a first rms surface roughness that isgreater than a second rms surface roughness of a non-textured area ofthe seal. The first rms surface roughness being greater than the secondrms surface roughness causes the patient contacting portion of the sealto have a silky feeling. This silkiness for the seal increases patientcomfort and the effectiveness of the seal and is used by the patientwithout impairing the sealing ability of the cushion. Because theremaining portion of the seal has less surface roughness, it appears tobe smooth and lightweight, enhancing the aesthetic appearance of theseal and, hence, user acceptance.

In another embodiment of the present invention, the seal includes afirst end portion adapted to be coupled to a mask shell, a second endportion for sealing engagement with a face of a patient, and a sidewallextending between the first end portion and the second end portion. Atleast a first portion of the second end portion includes a first rmssurface roughness that is greater than 700 microinches. In addition, atleast a second portion of the second end portion of the seal or a firstportion of the sidewall includes a second rms surface roughness that isless than 700 microinches. As noted above, this degree of surfaceroughness causes that portion of the seal to have a silky feel at thepatient contacting surface of the seal, increasing patient comfort. Italso prevents or reduces the sticky or tackiness associated withsurfaces with less rms surface roughness.

It is yet another object of the present invention to provide arespiratory mask having a shell with a first opening adapted to becoupled to a patient circuit and a second opening, and a seal of eitherembodiment discussed above coupled to the shell generally at the secondopening.

These and other objects, features, and characteristics of the presentinvention, as well as the methods of operation and functions of therelated elements of structure and the combination of parts and economiesof manufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limits of the invention. As usedin the specification and in the claims, the singular form of “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a respiratory mask according to theprinciples of the present invention shown schematically coupled to apressure support system;

FIG. 2 is a side view of the mask shown in FIG. 1;

FIG. 3 is a perspective view of the seal used in the mask of FIG. 1;

FIG. 4 is a sectional view of the seal taken along line 4-4 of FIG. 3and also shows a detailed sectional view of one exemplary configurationfor the surface roughness provided on the seal according to theprinciples of the present invention; and

FIG. 5 is a perspective view of a second embodiment of a seal with atextured surface portion according to the principles of the presentinvention;

FIGS. 6A and 6B are perspective views of a third embodiment of a sealwith a textured surface portion according to the principles of thepresent invention;

FIGS. 7A and 7B are perspective and side views, respectively, of afourth embodiment of a seal with a textured surface portion according tothe principles of the present invention;

FIG. 8 is a perspective view of another respiratory mask having a sealwith a textured surface portion according to the principles of thepresent invention; and

FIG. 9 is an exploded view of the mask shown in FIG. 8.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS OF THEINVENTION

FIGS. 1 and 2 illustrate an exemplary embodiment of a respiratory mask30 according to the principles of the present invention. Mask 30 isshown schematically attached to a pressure generating system 32 via apatient circuit 34, as is conventionally known in the art. Respiratorymask 30 includes a shell 36 and a seal 38 attached to the shell. Patientcircuit 34 is coupled to a port defined in a first side of the maskshell. Preferably, the patient circuit is connected to the mask shell soas to pivot or rotate relative to the mask shell and may or may not bedetachable therefrom. In short, any conventional coupling technique forjoining the conduit to the mask shell is contemplated by the presentinvention.

For purposes of the present invention, pressure generating system 32 isany device capable of generating a flow of breathing gas or providinggas at an elevated pressure. Examples of such pressure generatingsystems include a ventilator, CPAP device, or variable pressure device,e.g. an auto-titrating device, proportional assist ventilation (PAV®)device, proportional positive airway pressure (PPAP) device, C-Flex™device, Bi-Flex® device, or a BiPAP® device manufactured and distributedby Respironics, Inc. of Pittsburgh, Pa., in which the pressure providedto the patient varies with the patient's respiratory cycle so that ahigher pressure is delivered during inspiration than during expiration,or other pressure support device.

In the illustrated exemplary embodiment, an exhaust vent 40 is providedin patient circuit 34 for exhausting a flow of gas from the mask orconduit to ambient atmosphere. Such exhaust vents are conventionallyused in pressure support systems that use a single-limb, i.e., a singleconduit, to communicate a flow of gas to an airway of a patient. Thus,the present invention contemplates that exhaust vent 40 can be anyconventional exhaust vent, and can be located on the mask, such as onthe mask shell, on the patient circuit, at the mask shell/patientcircuit interface, or at any combination of such locations. The exhaustvent shown in FIG. 2 corresponds to that described in published U.S.application Ser. No. 10/119,673, entitled, “Exhaust Port Assembly for aPressure Support System,” Publication No. US 2003/0005931, the contentsof which are incorporated herein by reference.

Respiratory mask 30, including shell 36 and seal 38, can have any one ofan infinite number of configurations, shapes, and sizes. In theillustrated embodiment, shell 36 corresponds to that described in U.S.application Ser. No. 10/654,379, entitled, “Patient Interface WithForehead Support System,” the contents of which are incorporated hereinby reference. Mask shell 30 is preferably formed from rigid plastic,such as polycarbonate. As described in detail in the '379 application,and as illustrated herein, mask 30 includes an adjustable foreheadsupport 41. The forehead support is generally T-shaped and includes asupport arm 42, which is slideably connected to a forehead supportbracket 44. Forehead support bracket 44 includes a forehead pad 46disposed on the patient contacting side to engage the forehead of theuser. It is to be understood that the present invention contemplatesthat the forehead support assembly, and its individual components, canhave any one of a variety of configurations. The present invention alsocontemplates that the forehead support assembly can be eliminatedentirely.

In the illustrated embodiment, a headgear (not shown) attaches to mask30 via headgear clips 48. Headgear clips 48 attach to headgear straps(not shown), for example by inserting the headgear straps into slotsprovided on the clips. The headgear clips are selectively attachable tothe mask shell in any conventional manner. In this embodiment, theheadgear clips attach to each side of forehead support bracket 44 and toeach side of the lower portion of the mask shell. It can thus beappreciated that the headgear and head clip can have any configurationso as to be selectively attachable to the mask. It is to be furtherunderstood that the present invention contemplates eliminating all, or aportion, of the headgear clips an attaching the headgear straps to themask shell.

Seal 38 includes a first end portion 50 that couples to mask shell 36.In the illustrated embodiment, first end portion 50 is generallytriangular shaped and attaches to similarly-shaped opening provided in asecond side of the mask shell. In this embodiment, the mask shell andthe first end portion of the seal that attaches thereto are bothgenerally planer, i.e., both line in a linear plane. It should be notedthat the present invention contemplates that the mask shell and thefirst end portion of the seal can be contoured, when viewed in profile,so that first end portion 50, for example, does not lie in a commonplane.

It is to be further understood that the present invention contemplatesusing any conventional technique for attaching the first end portion ofthe seal to the mask shell. Such techniques include permanently bondingthe seal to the mask shell, for example, using adhesives, mechanicalfasteners, or molding the seal onto the shell such that the seal isselectively detachable from the mask shell.

In the illustrated embodiment, a lock ring 52 slips over the seal andengages a lip 54 defined on the first end portion of the seal. The lockring attaches to the mask shell in any conventional manner. For example,the present invention contemplates providing locking tabs 56 on lockring 52 that selectively attach to engaging portions of the mask shell.When coupled to the mask shell, the seal defines a chamber for receivinga portion of the patient when the mask is donned by the patient.Typically, a portion of the patient, such as the patient's nose, insertsinto the chamber so that the patient's airway is in fluid communicationwith the chamber.

Seal 38 includes a second end portion 60 for sealing engagement with aface of a patient. A sidewall 62 extends between first end portion 50and second end portion 60. Seal 38 is preferably a unitary structurethat attaches to a mounting portion of a mask shell or other supportstructure and provides a surface at second end portion 60 that contactsa surface of a patient. In the case of a nasal mask, for example, thesecond end portion contacts the area of the patient generally around thenose including over the bridge of the nose.

According to the principles of the present invention, a portion of theexposed surface of the seal at the second end portion includes atextured area 64, which is illustrated in the figures as a gray regionat second end portion 60 of the seal. The remainder of the seal isnon-textured, which is also referred to as being polished. Textured area64 of seal 38 corresponds to an area in which the surface of the seal isintentionally roughened so as to have a greater amount of surfaceroughness than a surface that is considered to be polished, which is thecase with the surface of the seal in conventional respiratory masks. Inthis embodiment, the surface roughness of textured area 64 is greaterthan the surface roughness at the other exposed surface of the seal,such as the exterior portion of sidewall 62.

The partial texturing of the seal eliminates or at least reduces theirritation caused by the polished surface of the cushion. This texturingprovided at the patient contacting portion of the seal also helpsprevent the seal from sticking to the skin. The texturing or increasedsurface roughness causes that portion of the seal to have a “silky”sensation, rather than a tacky or sticky feeling where there surface ismore polished, i.e., has less surface roughness. Increasing the surfaceroughness provides this highly comfortable feel contact without havingto change the seal in any other significant way.

For example, it is generally desirable to provide a clear silicone sealthat is highly transparent due to the surface being polished, i.e.,non-textured. Such as seal is generally transparent or opaque so thatthe seal has an overall “transparent look”. This “transparent look” forthe seal causes the seal to be perceived as being small andlight-weight, which is more aesthetically pleasing that a heavy-lookingseal. However, such a seal with its polished surfaces suffers from thedisadvantages noted above. The present invention corrects thesedisadvantages while still retaining the desirable features associatedwith the use of a transparent looking, i.e., polished, seal. In otherwords, the present invention, by providing a portion of the seal that istextured and a portion that is not, obtains the benefits of thetexturing, e.g., the silky feeling, as well as the benefits ofnon-texturing, e.g., the transparent, lightweight look for the seal.

At a microscopic level, no surface appears perfectly smooth. Allmaterials exhibit some degree of surface irregularities and bumps. Onemeasurement of surface roughness is the rms (root-mean-square) of theheight of the surface bumps, which is also referred to as the “rmsroughness” or “rms surface roughness”. This height is illustrated asdistances d₁ and d₂ in FIG. 4. In an exemplary embodiment of the presentinvention, textured area 64 of seal 38 has an rms surface roughnessgreater than 700 microinches. That is, distance d₁ in FIG. 4 isgenerally greater than 700 microinches rms. In a more specificembodiment of the present invention, the textured area has an rmssurface roughness in a range of 750-1,500 microinches. The polishedsurface, i.e., the non-textured surface, of the seal preferably has anrms surface roughness that is less than 690 microinches. That is,distance d₂ is generally less than 690 microinches rms, and ispreferably in a range of 1-100 microinches rms.

A further embodiment of the present invention contemplates that thetextured area 64 of seal 38 has an rms surface roughness greater than 10micrometers (μm) which is equivalent to approximately 394 microinches(pin). In this embodiment, the polished surface, i.e., the non-texturedsurface, of the seal has an rms surface roughness that is 10 micrometersor less.

The present invention contemplates that increasing the surface roughnessof a portion of the seal can be accomplished using any conventionaltechnique. For example, one embodiment of the present inventioncontemplates using a high precision photo etching technique on theportion of the tool used to form this textured area of the seal. Thisphoto etching increases the surface roughness of the tool where desired,so that the textured area is molded into the seal during the moldingprocess. The non-textured area of the mold defines the polished surfaceof the seal. To those skilled in the art of molding, the polished moldis commonly referred to an SPI/SPE standard mold finish #1 (#3 DiamondPolish, RMS 0.5-1.0 microinches) and SPI/SPE standard mold finish #2(#15 Diamond Polish, RMS 1.0-2.0 microinches).

The present invention also contemplates that the textured area can beformed on the seal after the seal molding process. That is, the seal canbe formed such that all surfaces are polished, i.e., have an rms surfaceroughness less that 690, and the textured area is formed on the sealsurface subsequent to the molding of the seal. Forming the textured areaon the molded seal can be accomplished, for example, by cutting orscoring the seal with micro-abrasions. Forming the textured area on themolded seal can also be accomplished by adding a texturing on the seal,for example, by spraying or applying micro-particles on the molded seal.It is to be understood that the present invention is not intended to belimited to these exemplary techniques for forming the textured area onthe molded seal. Quite the contrary, the present invention contemplatesusing any conventional technique for forming the textured area on themolded seal.

In the embodiment illustrated in FIGS. 1-4, the entirepatient-contacting surface at the generally triangular-shaped second endportion of the seal includes the textured area of increased surfaceroughness. Textured area 64 is disposed around the entire perimeter ofthe patient contacting surface of the second end portion of the seal.This configuration ensures that the portion of the seal contacting thepatient will include the texturing. It is be understood, that thepresent invention contemplates other configurations, patterns, andarrangements by which the textured area is disposed on the seal. Forexample, the present invention contemplates providing the textured areaonly at select locations on the seal, such as at the bridge of the noseor at the portion of the seal that underlies the nose. The discretelocations for the textured areas can be selected based on the desiredperformance characteristics for the seal and/or user preference. It canbe appreciated that the myriad of possible configurations for thetextured area are nearly infinite. Thus, no attempt is made to try tolist the possible configurations other than to make note that there isno limit on such configurations.

It can also be appreciated that the shape of the seal and other featuresof the seal can be varied while still keeping within the spirit of thepresent invention. For example, in the embodiment illustrated in FIGS.1-4, seal 38 is a two-flap seal. In this exemplary embodiment, a firstflap 70 is operatively connected to side wall 62, and a second flap 72is also operatively connected to the side wall underlying the firstflap. It is to be understood that the first flap and the second flapneed not be connected to the sidewall. Instead, they may individuallyand separately connect to the mask shell. In addition, the first flapand the second flap can have any desired configuration. The shapes andsizes of the first and second flaps can be complimentary to one anotheror entirely dissimilar. Although not shown, a third or more flaps canalso be added if desired.

It is to be understood that the second flap may be entirely eliminated.A seal 38′ showing a single flap configuration is shown, for example, inFIG. 5. Seal 38′ is generally similar to seal 38 in FIGS. 1-4 exceptthat it is a single-flap design. In addition, as seen in FIG. 5, seal38′ includes a first end portion 50′ that is generally triangularshaped, a second end portion 60′ for sealing engagement with a face of auser, a sidewall 62′ that extends between first end portion 50′ andsecond end portion 60′, and a textured area 64′.

FIGS. 6A and 6B illustrate a third embodiment of a seal 72 with atextured surface 74 according to the principles of the presentinvention. A unique feature of seal 72 is that a flap 76 is provided ata second end portion 78 of the patient contacting area of the seal thatoverlies the bridge of the patient's nose. Flap 76 seals over thepatient's nose when the mask having seal 72 is donned by the patient.The user's nose inserts into opening 78.

FIGS. 7A and 7B illustrate a fourth embodiment of a seal 80 with atextured surface 82 according to the principles of the presentinvention. This embodiment shows that the present invention contemplatesproviding the textured surface on other types of patient interfacedevices, not just on a traditional mask type device. Seal 80 is a nasalcannula type of patient interface device having a first end 84 thatattaches to a seal support structure (not shown). Seal 80 correspond tothe cannula-type nasal interface device shown and described in pendingU.S. provisional patent application No. 60/496,059 filed Aug. 18, 2003entitled, “Patient Interface Assembly and System Using Same”, thecontents of which are incorporated herein by reference.

Seal 80 includes a nasal cushion 86 and a pair of laterally spaced nareselements 88 at its distal end for insertion into the nostrils of thepatient. The body of nasal cushion 86 includes a hollow chamber andextends from an oval shaped opening at first end 84 to laterally spacedoutlet legs 90. Each outlet leg 90 is provided with one of nares element88. The body of nasal cushion 86 curves about an axis substantiallyperpendicular to a plane separating the two nares elements. Each nareselement 88 has an opening 92 to communicate with the nasal passages ofthe patient. Each of nares elements 88 is substantially dome-shapedhaving an elliptical base proportional to anthropometrical data of anostril opening. Nasal cushion 86 is preferably formed from a softcushiony material, such as silicone, appropriately soft thermoplasticelastomers, closed cell foam, or thin materials. Tabs 94 are provided onopposing sides of nasal cushion 86 to assist in aligning and securingthe seal with a receiving end the seal support (not shown) of thecradle.

In the illustrated embodiment, textured area 82 is provided oversubstantially an entire area of dome-shaped nares elements 88. It is tobe understood that the textured area can be provided over only a portionof each nares element in a select pattern or a select locations.

FIGS. 8 and 9 illustrate yet another respiratory mask 100 having a seal102 with a textured surface area 104 according to the principles of thepresent invention. In this embodiment, seal 102 is disposed over asecond seal 106, both of which are coupled to mask shell 108, eitherpermanently or selectively. Second seal 106 can have any conventionalconfiguration. However, a preferred exemplary embodiment contemplatesthat seal 106 is a gel seal of the type described in U.S. Pat. Nos.5,647,357; 5,884,624; and 6,397,847 the contents of each of which areincorporated herein by reference.

Respiratory mask 100 can have any of a variety of configurations.However, in a preferred exemplary embodiment, respiratory mask 100 andits associated features correspond to the patient interface assembliesshown and described in pending U.S. patent application Ser. No.10/654,379 entitled, “Patient Interface With Forehead Support System”,filed Sep. 3, 2003, and Ser. No. 10/629,366 entitled, “Patient Interfaceand Headgear Connector” filed Jul. 29, 2003, the contents of both ofwhich are incorporated herein by reference.

Respiratory mask 100 includes a forehead support 110 operatively coupledto mask shell 108. In a preferred embodiment, the forehead support isadjustable relative to the mask shell to control a position of theforehead support relative to the mask shell. A forehead pad 112 isdisposed on the forehead support. At least a portion of the forehead padincludes a textured area 114 having an rms surface roughness asdiscussed above with respect to textured area 64. That is, in theillustrated embodiment, forehead pad 112 includes a textured area 114and a non-textured area 116. It is to be understood that the surface ofthe forehead pad can be entirely textured, can have multiple texturedareas, and the textured area or areas can have any one of a variety ofdifferent sizes, shapes, patterns, or configurations. In a preferredembodiment, the rms surface roughness of the textured area on theforehead pad is substantially the same as that of the textured area onthe seal. It should also be noted that texturing can also be provided onthe forehead pads shown in FIG. 1. In addition, as seen in FIG. 9,respiratory mask 100 includes a user circuit 34′ and headgear clips 48′.

The present invention contemplates that the seal is a silicone rubber,or at least the portion of the seal that contacts the user is a siliconerubber. The texturing can be provided using one or more of a variety oftechnologies, such as laser texturing of injection molds, moldingmicro-spheres into the silicone, molding textile materials into thesilicone, attachment a patch with the required texture to a surface ofthe seal. Still other techniques for forming the textured patterns arecontemplated, such as laser etching the molded silicone, lithographictechniques, and any other technique that can be controlled so as to forma patterned or structured surface.

Although the invention has been described in detail for the purpose ofillustration based on what is currently considered to be the mostpractical and preferred embodiments, it is to be understood that suchdetail is solely for that purpose and that the invention is not limitedto the disclosed embodiments, but, on the contrary, is intended to covermodifications and equivalent arrangements that are within the spirit andscope of the appended claims.

What is claimed is:
 1. A respiratory mask comprising: (a) a shell; (b) aseal adapted to be coupled to the shell; (c) a forehead supportoperatively coupled to the shell; and (d) a patient contacting foreheadpad operatively coupled to the shell, wherein at least a portion of theforehead pad includes an rms surface roughness greater than 10micrometers.
 2. The respiratory mask of claim 1, wherein the foreheadpad includes a non-textured area having an rms surface roughness of 10micrometers or less.
 3. The respiratory mask of claim 1, wherein anentire user-contacting surface of the forehead pad has an rms surfaceroughness greater than 10 micrometers.